Stickney etal
scintillation scanner



y 3, 1966 J. B. STICKNEY ETAL 25,014

SCINTILLATION SCANNER 5 Sheets-Sheet 1 Original Filed June 1 1959 m w k2 INVEN'T S H a, STIC Y LEMMERMANN JO CL ENCE E RING 6 BY Ma CARL E. HERROLAND W. C

AT TORNE YS May 3, 1966 J. a STICKNEY ETAL R 26,014

SCINTILLATION SCANNER Original Filed June 1, 1959 5 Sheets Sheet 2 FIG.2

INVENTORS JOSEPH a. sncmsv CLARENCE E. Lsuusmml, CARL E. HERRING 8ROLAND w. CARLSON ATTORNEYS J. :LTICKNEY ETAL 26,014

May 3, 1966 S015 iILLA'IION SCANNER 5 Sheets-Sheet 5 Original Filed June1, 1959 a @Zg mm a fiWV/wfm INVENTORS m M Y N E 5 a m m ma N w wimufly RER O HEMW I T m b T ME A ERLA SAMW. wacky Y a B y 1966 J. B. STICKNEYETAL 26,014

SCINTILLATION SCANNER Original Filed June 1, 1959 5 Sheets-Sheet 4 1 1I20 50 [i F" 49 I i 44 H 45 1 g L- 43 52 4I a 1 40 L ,4 E! M ly23 k P 229 INVENTORS JOSEPH B. STICKNEY CLARENCE E. LEMMERMANN,

CARL E. HERRING 8 ATTORNEYS May 3, 1966 Original Filed June 1, 1959 5Sheets Sheet 5 i IBI L0 to 2 MW 3 J L 1 co m E m E v :r 2 I $4 L I x 1 Im I m m N m m o I W q 3 I I m g Q I 9 1M0 3 a G a g i 0: m g Q m 9 9 w Qm m INVENTORS Q Q Q JOSEPH a. STICKNEY, O CLARENCE E. LEMMERMANN, C) yCARL E. HERRING a ROLAND w CARLSON 25 6%; M N ATTORNEYS United StatesPatent 26,014 SCINTILLATION SCANNER Joseph B. Stickney, Rocky River, andClarence E. Lemmermann, Cleveland, Ohio, Carl E. Herring, Palo Alto,Calif., and Roland W. Carlson, Euclid, Ohio, assignors to Picker X-RayCorporation, Waite Mfg. Div., Inc., Cleveland, Ohio, a corporation ofOhio Original No. 3,070,695, dated Dec. 25, 1962, Ser. No. 817,403, June1, 1959. Application for reissue Apr. 22, 1965, Ser. No. 460,608

29 Claims. (Cl. 250-715) Matter enclosed in heavy brackets appears inthe ol'i inal patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention pertains to a class of mechanisms known as ScintillationScanners.

With modern medical techniques many studies are made by causing thepatient to swallow or otherwise absorb quantities of radioactivesubstances. The distribution of the radioactive substance in thepatients body is then studied. Such studies are useful for many purposessuch as the locations of cancerous tissue in the human body anddetermination of the performance of body organs such as the thyroidgland.

This invention pertains to an improved mechanism for conducting suchtracer studies. These mechanisms are known as Scintillation Scanners."They include a means to move a scintillation probe over an area beingstudied and a means to provide a graphic reproduction of the activitymeasured by the probe.

The scintillation scanner of this invention is a portable mechanismwhich can readily be moved to the patients bed or other location where astudy is to be conducted. The probe is supported cantilever fashion topermit it to be positioned over the body of the patient, or other objectto be studied. The cantilever type support affords great flexibility inconducting a study while avoiding the problem of suspending unsightly,heavy, bulky mechanisms over the patient. The suspension of unsightly,heavy mechanisms over a patient causes both problems in supporting themechanism and psychological fear in the patient as well.

The mechanism is also designed to permit a probe supporting boom to bemoved about manually and with facility until the probe is positioned ina desired location. After the probe has been positioned, the boom isoperably connected to an automatic drive means to move the probe througha predetermined geographic pattern for a tracer study. The scan can beconducted by moving the probe-at a selected speed across a series ofparallel paths which are at selected spaced intervals.

A light source and a stylus are carried by the boom and theysimultaneously move with it. This simultaneous movement permitsproduction of both graphic and photographic reproductions of theactivity measured by the probe during the scan.

Accordingly, one of the principal objects of this invention is toprovide a novel and improved scintillation scanner which is simple andeasy to use, and which has adjustments to permit a wide variety oftracer studies to be conducted.

A related object of this invention is to provide a novel and improvedscintillation scanner made in accordance with the foregoing objective,which scanner is portable.

Another object of this invention is to provide a novel and improvedscintillation scanning device in which a probe is supported cantileverfashion over the object being studied, such that essentially only theradiation responsive mechanism is supported over the object.

A further object of this invention is to provide a novel and improvedscintillation scanning device which has a Re. 26,014 Reissued May 3,1966 reciprocal table boom for supporting a scintillation probecantilever fashion, and which also supports means for producing agraphic image.

A related object of the invention is to provide a mechanism made inaccordance with the preceding object, which mechanism includes both anapparatus to produce a photographic image and an apparatus to produce agraphic image either alternately or simultaneously.

Another object of the invention is to provide a novel and improvedmechanism for moving the boom over a predetermined path, which mechanismis adjustable both as to the rate of reciprocation longitudinally andthe transverse spacing between such reciprocations.

A similar object of this invention is to provide a movement controlmechanism wherein the longitudinal reciprocal means is inactive whentranslational movement is obtained.

Another object of this invention is to provide a novel and improvedmechanism for moving the boom, which mechanism can be facilelydisconnected for manual positioning of the boom and thereafter connectedto commence an automatic scan from the selected position.

Another object of this invention is to provide a novel and improved scancontrol mechanism in which the ex tremes of the scan are selectivelyadjustable to provide a scan of any selected size, up to the maximumcapacity of the machine.

Another object of this invention is to provide a novel and improvedscintillation scanning device which will automatically conduct a scanand automatically shut itself off when that scan has been concluded.

A more special object of the invention is to provide a novel andimproved stylus of simple inexpensive construction for providingimproved graphic studies.

A related object of the invention is to provide a novel and improvedstylus support.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawings, in which:

FIGURE 1 is a perspective view of the device;

FIGURE 2 is a sectional view of the upper portion of the device as seenfrom the plane indicated by the line 2-2 of FIGURE 1;

FIGURE 3 is a sectional view of the upper portion of the device as seenfrom the plane indicated by the line 3-3 of FIGURE 2;

FIGURE 4 is a sectional view above the probe elevation and depressionmechanism as seen from the plane indicated by the line 4-4 of FIGURE 1;

FIGURE 5 is a sectional view of a fragmentary portion of the device asseen from the plane indicated by the line 5-5 of FIGURE 3;

FIGURE 6 is a sectional view of a fragmentary portion of the device asseen from the plane indicated by the line 66 of FIGURE 2;

FIGURE 7 is a fragmentary sectional view as seen from the planeindicated by the line 77 of FIGURE 2;

FIGURE 8 is a fragmentary sectional view as seen from the planeindicated by the line 88 of FIGURE 5;

FIGURE 9 is an elevational view of the stylus and support mechanism withparts broken away and removed and as seen from the plane indicated bythe line 99 of FIG- URE l; and,

FIGURE 10 is a wiring diagram of the scan control mechanism.

Referring to the drawings and to FIGURE 1 in particular, a housing isshown generally at 10. Base members 11 are provided which form a part ofthe frame structure of the housing. The base members 11 are supported bywheels 12 which give the mechanism mobility.

A plurality of control panels 13 are provided in the front wall of thehousing. The control panels 13 include the various dials and knobsneeded to control a scintillation circuit. This circuit includes aconductor 14 which transmits impulses from a scintillation probe 15. Theimpulses are transmitted, monitored, and amplified. The electricimpulses are then transmitted through conductor 55 to a stylus 16 and toa light source 17 through a conductor 19. There are many well knowncircuits which are suitable for this purpose. A preferred circuit isdisclosed in copending application for patent Serial Number 820,508,filed June 15, 1959, by Splain, Stickney, and Herring under the title,Scintillation Scanner Circuit. This circuit does not form a part of thepresent invention and accordingly is not shown in detail here.

In the upper portion of the face of the housing another, or uppercontrol panel 18 is provided. This upper panel 18 includes variousoperator controlled parts for selective control of the movement of theprobe for or during a study. These parts will subsequently be describedin greater detail.

A boom 20 is supported in a space 21 in the upper portion of thehousing. The boom 20 supports the scintillation probe 15, the stylus 16,and the light source 17. The boom 20 is supported by a transversecarriage 22. The boom 20 is movable reciprocally along a longitudinalpath relative to the carriage 22 and the housing 10. The boom 20 issupported for such reciprocal travel by spaced pairs of support rollers23 which are rotatably supported at the front and the rear of thecarriage 22 and by upper guide and support rollers 24. The upper rollers24 are provided at the front and the rear of the carriage 22 to coactwith the vertical support rollers 23 in holding the boom 20 verticallypositioned. The upper support rollers are preferably, as shown,connected to the carriage 22 and in contact with the boom 20.

Spaced side rollers 25 are also preferably mounted on the carriage 22and are coactable with the boom 20. The side rollers 25 hold the boom ina selected transverse position against shifting relative to the carriage22 in a horizontal path. Preferably, the side rollers 25 are providedboth in the front and the rear of the carriage 22.

The carriage 22, in turn, is supported on front and rear guide tracks26, 27, for rectilinear travel along a path which is transverse to thepath of longitudinal boom travel. Since the boom 20 is carried by thecarriage 22, the boom will move transversely with the carriage. Theguide tracks 26, 27 form a part of the frame structure of the housing10. A plurality of spaced carriage support rollers 28 and a plurality ofcoacting carriage positioning and support rollers 29 carry the weight ofthe carriage 22 on the guide tracks 26, 27. The lower coacting rollers29 are preferably paired with the upper or carriage support rollers 28.A plurality of horizontal positioning rollers 30 are provided to retainthe carrier in its rectilinear path of travel.

A light source support 32 is carried by the boom and forms a part of it.The light source support 32 extends through a light-tight region 33formed in the housing. The light source 17 is carried by the support at32 and within the light-tight region 33.

A pair of constant tension coil springs 34, 35 are carried at the frontand the rear of the housing and extend across access apertures to thelight-tight region 33. Suitable springs are sold under the trademarkNegator by the Hunter Spring Company. The light source support 32projects through apertures in the Negator springs 33, 34. The ends ofthe Negator springs are carried on spaced rotatable coils 36 which aremounted at either end of each light-tight region access aperture. Thesprings 34, 35 move back and forth with the light source support 32coiling and uncoiling on the reels 36 to maintain the region 33 lighttight.

A suitable film access slot 37 is provided to permit the insertion ofthe means to hold a sheet of photographic film 38 is exposed by thelight source 17 when a scan is being conducted, as will subsequently bedescribed in more detail.

A graph support 40 projects rearwardly from the housing to hold a sheetof graph paper 41. The sheet of paper 41 is of a type which silentlyrecords a graphic visual image when an electric charge is passed throughthe stylus 16 to burn a dot into the paper. One such paper is known asTeledeltos paper and sold by the Western Union Company. The paper 41 isheld in position by a plurality of magnets 42.

The stylus 16 is carried in stylus support 43 which may be ofelectrically insulating material. The stylus support 43 has a throughaperture 44 which receives the stylus 16. A stylus positioning member 45is provided. The positioning member 45 has a pivot end 46 pivotallymounted in a slot 47 formed in the stylus support 43. The pivot 46 ismovable rectilinearly in the slot 47 against the action of a spring 48.The stylus positioning member 45 has a stylus abutment part 49 whichpresses against the stylus 16 under the urging of the spring 48.

The stylus abutment part 49 is movable vertically. The vertical travelis limited by upper and lower ends of a notch formed in the stylussupport 43. In the position shown in FIGURE 9 the stylus abutment part49 is against the lower end of the notch 50 and the stylus is held in agraph producing position. To raise the stylus, one merely elevates thestylus positioning member 45. The positioning member 45 compresses thespring 48 until the positioning member has passed the horizontalposition which, in this mechanism, is the overcenter position.Thereafter, the abutment part 49 will urge the stylus upwardly under theurging of the spring 48 until the abutment part 49 contacts the top ofthe notch 50 in the position shown in phantom in FIGURE 9.

One of the outstanding advantages of this invention is achieved throughthe novel stylus provided. The stylus in its preferred and disclosedform is a drawing pencil sharpened at both ends. it has been discoveredthat the conventional pencil lead is a very excellent conductor whichforms an outstanding electric stylus for burning" dots in the graphpaper 41. With the mechanism shown, the stylus is easily removable bycompressing the spring 48 and thereafter either or both ends may besharpened as needed.

As is well known, the pencil lead is in reality powdered graphite with abinder. The graphite and binder forms a conductor bar which isdesignated by the numeral 51. It is, as is well known, an elongated barwhich fills a tubular passage in wood housing 52 and projects throughboth ends of the housing. The graphite serves as the electricalconductor for transmitting the electric impulses to be recorded. A 4H"pencil is ideal for this purpose having the appropriate amount ofconductivity and sufficient hardness to retain a point for protractedperiod of operation.

A conductor cap 53 telescopes over the upper end of the stylus 16. Theconductor cap 53 has a contact 54 which is in electrical contact withthe conductor bar 51 of the stylus 16. The conductor 55 which transmitselectrical impulses for the stylus, is connected to the contact 54.

The probe 15 is supported on a support bar 57. The support bar 57projects through an aperture 58 formed at the outer end of the boom 20.The support bar 57 includes a rack which engages gear 59. The gear 59forms a part of a gear train which is driven by handles 60 which arejournaled in the boom 20. Thus, rotation of the handles 60 in a selecteddirection will elevate or de press the probe 15. The purpose of thisheight adjust ment will subsequently be described in more detail.

Another of the outstanding advantages of this invention resides in theautomatic mechanism for driving the boom in reciprocal paths bothlongitudinally and transversely. A scan motor 128 is carried on a scandrive bracket 62. The bracket 62 is pivotally mounted on a pair ofsupports 63 which form a part of the carrier 22. The scan drive motorhas a worm gear 64 mounted on its shaft. The worm gear 64 drives apinion gear 65 which is carried by a shaft 66. The shaft 66 is journaledin the bracket 62.

The shaft 66 has a drive gear 67 fixed to its upper end. The drive gear67 engages a rack 68 formed alongside of the boom 20. It will be seenthat when the gear 67 and the rack 68 are in engagement, rotation of thescan motor 128 in one direction will drive the boom 20 rectilinearly inone direction relative to the carrier 22. Reversing of the direction ofthe motor 128 will cause rectilinear movement of the boom 20 in theopposite direction relative to the carrier 22.

Movement of the carrier 22 and the supported boom 20 transverselyrelative to the housing is accomplished by causing an indexing motor 110to operate. The indexing motor 110 is mounted on the housing and isconnected to a gear train 70. The gear train 70 drives a screw 71 whichis journaled in the housing 10. The screw 71 is selectively engaged by asplit nut shown at 72.

The split nut 72 has upper and lower screw engaging sections 73, 74. Thescrew engaging portions 73, 74 are slidably carried on a pair of guidepins 75 which are fixed to the carriage 22. The nut 72 includes upperand lower spring retaining members 76, 77. Upper and lower springs 78,79 are positioned between the upper spring retainer 76 and the upper nutsection 73 and between the lower spring retainer 77 and the lower nutsection 74, respectively. The springs 78, 79 urge the nut sections 73,74 toward and into engagement with the screw 71.

In the arrangement thus far described, the gear 67 is in engagement withthe rack 68 and the split nut 72 with the screws 71 to provide drivingrectilinear movement of the boom relative to the carriage and of theboom and carriage relative to the housing. In conducting a tracer study.it is desirable to be able to shift the probe manually to a desiredposition, both to locate the center of a scan to be conducted and toposition the probe for the start of the scan. One of the outstandingadvantages of this invention is the novel and improved mechanism forpermitting the manual adjustment of the probe.

A drive mechanism control bar 80 is rotatably supported by the carriage.The control bar 80 is journaled in a pair of spaced brackets 81, FIGURE5, provided at the front and the rear of the housing. A control barhandle 82 is provided at the front end of the control bar 80 tofacilitate manual rotation of the control bar 80. The control bar 80 isoperatively connected to the split nut 72 and the gear 67 to move theminto and out of engagement with the screw 71 and the rack 68,respectively.

When the control 80 is rotated from the engagement to the disengagementposition, a scan control cam 85 acts against a lip 86 on the pivotal camsupport bracket 62. This action pivots the bracket 62 against the actionof a scan bracket support spring 87, FIGURE 6, positioned between thebracket 62 and the carriage 22. Pivoting of the bracket 62 shifts thegears 67 out of engagement with the rack 68 to permit the boom to beshifted longitudinally and relative to the carriage 22.

An indexing disconnection gear 88 is also mounted on the control bar 80.The disconnection gear 88 rotates simultaneously with the control bar 80and the scan control cam 85. Rotation of the gear 88 causes rotation ofthe split nut control gear 89 causes a split nut cam 90 to rotatespreading the upper and lower split nut sections 73, 74 to disengage thesplit nut from the screw 71. Disengagement of the split nut 72 permitsthe carriage 22 to be moved transversely relative to the housing.

When the handle 82 is released, the springs 78, 79 will urge the splitnut 72 back into engagement with the screw 71 and the spring 87 willurge the scan drive gear 67 back into engagement with the rack 68.

6 INDEXING CONTROL CIRCUIT Another of the outstanding advantages of thisinvention resides in the indexing control circuitry. This circuitry willcause the boom to reciprocate longitudinally at any selected speedwithin a wide range. In addition, when the boom reaches one end of itslongitudinal movement, it is indexed transversely automatically anyselected distance within a relatively wide range of indexing movement.

The power for the scanning and indexing movement of the boom is providedthrough a suitable source of electric potential designated in FIGURE 10as L -L A primary 102 of a constant voltage transformer is connected tothe source of electric potential L -L A main switch is series connectedto the primary 102. With the main switch 100 in the closed position, theprimary 102 is activated to induce current in a secondary 103.

One side of the secondary 103 is series connected to a scan controlswitch 101. The scan control switch 101 is connected to one side of thereversible A.C. indexing motor by a conductor 104. The other side of thesecondary 103 is series connected to a pair of normally closed limitswitches 105, 106. The limit switches 105, 106 in turn are seriesconnected through a conductor 107 to a normally open solenoid activatedAC. motor actuation or control switch 108. The other side of the motorcontrol switch 108 is connected through a conductor 109 to a selectorswitch 113. A selector switch 113 is selectively conncctable to eitherof the two terminals 115, 116 on the indexing motor 110. The selectionswitch 113 permits the indexing motor to rotate in a selected directionwhenever the switches 100, 101, 105, 106 and 108 are closed.

A winding of a speed control variable transformer 117 is connected tothe switches 101, 106 by conductors 114, 118 respectively. Thus, thewinding of the variable transformer is connected in series with thesecondary 103 of the constant voltage transformer and in parallel withthe AC. indexing motor 110.

The output of the variable transformer 117 is connected throughconductor 119 to a normally closed solenoid activated armature controlswitch 120. The switch 120 is, in turn, connected through a conductor121 to an armature rectifier 122. The output of the armature rectifier122 is connected through conductors 123, 124 to a solenoid actuatedreversing switch 125. The revers ing switch 125 is connected throughconductors 126, 127 to the armature of a direct current scan motor 128.

One side of field 129 of the scan motor 128 is connected to a fieldrectifier 130 by a conductor 131. A variable resistance 132 is connectedto the other side of the field 129. The variable resistance 132 is usedto adjust the range of the variable transformer 117 which controls thespeed of the direct current motor 128 within the selected speed range.The variable resistance 132 in turn is connected to the other side ofthe field rectifier 130 by conductor 134.

The field rectifier 130 is connected to the scan control switch 101 by aconductor 136. The rectifier 122 and the armature of the motor 128 arein parallel, across the secondary 103, with the rectifier 130 and theconnected field 129 and also with the indexing motor circuit. Conductors160, 161 respectively connect the rectifiers to the limit switches 105,106 to complete these parallel circuits.

A normally closed solenoid activator and control 133 is connected to thesecond rectifier 130 by a conductor 135 as a part of a circuit whichparallels the field 129. A time delay capacitor 138 is connected inparallel with a normally closed switch 133 by conductors 139, 149.

The field rectifier 130 is also connected to a solenoid 140 by aconductor 141. The solenoid 140 controls a direction conditionmaintenance switch 142. The other side of the solenoid 140 is connectedthrough a conductor 143 to a normally open reversing limit switch 144.The normally open reversing limit switch 144 is connected through theconductor 145 to the direction maintenance switch 142. The other side ofthe switch 142 is connected through the conductor 146 to switch 144.

A normally open reversing limit switch 144 is connected in parallel withthe switch 142 and in series with the normally closed switch 147 and therectifier 130, by conductors 148, 152.

A time delay switch 15!) is mechanically connected to the normally openreversing switch 144. The time delay switch 150 is open when thereversing switch 144 is open. A second time delay switch 151 ismechanically connected to the normally closed reversing switch 1.47. Thesecond time delay switch 151 is open when the normally closed reversingswitch 147 is closed.

The time delay switches 150, 151 are each connected in parallel with oneanother and in series with a motor control or time delay solenoid 152 bya conductor 153. The other side of the time delay solenoid 1.52 isconnected through conductors 154 to the switch 133 and the conductor149. The solenoid 152 controls the normally closed switches 120, 133 andthe normally open switch 108, all of which switches are mechanicallyconnected.

A time delay control potentiometer 155 is shunted around the relay 152by connections through conductors 156, 157. The conductors 156, 157 areconnected to the conductors 154. 153 respectively.

\Vhen the switches are in the position shown in the drawings, the directcurrent scan motor 128 will operate to shift the boom 20 longitudinally.As the boom 20 reaches one end of its longitudinal travel, the reversingswitch 144 and the time delay switch 150 are closed. Closing of thereversing switch 144 closes the circuit for activating the solenoid 140.Thus, with the switch 144 closed, the current will flow from the secondrectifier 130, through the conductor 141, thence, through the solenoid140 to the conductor 143, through the switch 144, the conductor 148 andthe switch 147, and thereafter through the conductor 158 to theotherside of the second rectifier 130. Activation of the solenoid 140closes the relay switch 142 and shifts the mechanically connectedreversing switch 125 to reverse the polarity of the conductors 126, 127and thereby reverse the direction of the scan motor 128.

The closing of the time delay switch 150 passes current through theconductor 153 to energize the solenoid 152. This opens the normallyclosed switch 120 to de-energize the armature rectifier 122 and therebyile-energize the armature of the motor 128. It also closes the switch108 to start the alternating current indexing motor 110. Rotation of theindexing motor 110 shifts the boom 20 transversely to the next scanposition.

The solenoid 152 will hold the switches 133, 120 open and the switch 108closed so long as current flows through the conductor 154 and thencethrough the conductor 149 to the capacitor 138. The length of time whichsuch current flows is determined by adjustment of the potentiorneter155. As soon as the capacitor 133 is charged, the flow of currentthrough the solenoid 152 will stop and the switches 120, 133 will returnto closed positions to start the scan motor. At the same time the switch108 will open to stop the indexing motor 110. After the switch 133closes, the condenser 133 will be discharged because the switch 133forms a parallel circuit with the condenser 138.

Once the switch 120 is closed the circuit through the armature of motor128 is again complete and the scan motor will begin to operate, thistime in a reverse direction. As the scan motor commences to operate inthe reverse direction, the boom 20 will move away from the switches 144,150 permitting them to open. Even though the switch 144 opens. theswitch 1*.2 is held in a closed position because a circuit to maintainthe solenoid 140 energized is maintained through the normally closedreversing switch 147 and the switch 142.

When the other end of a scan reciprocation is reached the reversingswitch 147 is opened. Opening of the switch 117 breaks the circuitactivating the condition maintenance solenoid 143. As soon as thecircuit to the solenoid 140 is broken, the switch 142 will open and themechanically connecting reversing switch 125 will return to the positionshown in the drawings and again reverse the scan motor. At the same timewhen the switch 147 is opened, the time delay switch 151 is closed toactivate the solenoid 152. Activation of the solenoid 152 will againdie-energize the armature rectifier 122 and it will also activate theindexing motor 110 to again index the boom.

When the boom reaches the end of its travel in the direction selected bythe positioning of the selector switch 113. either the limit switch orthe limit switch 106 will be opened to stop the entire mechanism.

Referring again to the drawings which disclose the mechanical apparatus,a pair of switch housings 170 are shown positioned at the front and therear of the housing. These are best seen in FSGURE 2. One of theseswitch housings may hold the reversing switch 144 and the time delayswitch 159 while the other of the housings will conlain the reversingswitch 147 and the time delay switch 151.

A pair of adjustable reversing switch activation members 171 arepositioned on the light source support 32. The reversing switchactivation members 171 are movable along the slight source support bar32 to any desired position. The switch activation members 171 activatethe reversing and time delay switches. Thus, the extent of thelongitudinal travel is adjusted by positioning the switch activationmembers 171.

The limit switches 105, 106 are positioned at opposite ends of thecarriage 22. These switches 105. 106 are best seen in FIGURE 3. A pairof limit switch actuation members 162 are adjustably carried on asupport bar 163. The support bar 163 extends across the front of thehousing to place the limit switch actuation members in a position whichis convenient for the operator. The limit switch actuation members 162are adjustable transversely of the housing. When a scan is conducted,the carriage 22 is shifted translersely periodically by the indexingmotor until one of the limit switches 105, 106 engages one of theactuation members 162. This engagement opens a limit switch and stopsthe entire mechanism.

OPERATION OF THE DEVICE Since this device is designed primarily formedical use, the operation of the device will be described by describingthe conduction of a medical tracer study in detail.

After the patient has swallowed a quantity of radioactive material andsuificient time has passed for the material to be concentrated in thearea to be studied, the patient is normally placed in a prone positionon a table or bed. The machine is then moved alongside of a bed withprobe 15 and the supporting boom 20 extending over the patient. Thescanning circuit is then actuated. The control bar 80 is rotated todisengage the carriage and boom shifting mechanism to permit the probeto be moved manually to a desired position.

Next the probe is positioned at the approximate desired location fromthe patient. There the handles 60 are rotated to elevate or depress thesupport bar 57 and the supported probe 15 to position the probe :1selected space from the patient. The probe 15 may be rotativelysupported on the base of the bar 57 as seen at 165, to permit the probeto be rotated to a desired angle.

The probe and boom are shifted longitudinally and transversely todetermine both the horizontal extent of the scan to be conducted and thecenter of concentraion of the radioactive substance. This can befacilitated through the use of an audible sound which is responsive toradioactivity. The circuitry tor such audible sound is described incomplete detail in the previously cross-referenced copending applicationfor patent.

Once the size of the study to be conducted has been determined, thelongitudinal switch activation members 171 are placed in appropriatepositions to limit the extent of longitudinal travel. The boom andcarriage are moved to one side of the study area, say the right side.The left hand of the two transverse limit switch activation members 162is then positioned appropriately at the left-hand extremity of thestudy. The right-hand limit switch activation member 162 is not neededfor a rightto-left study, so it may be shifted to the right and out ofthe way;

Next, the selector switch 113 is positioned for indexing movement of themotor 110 to drive the carriage 22 from the right to the left. With theprobe at the righthand side of the study and positioned at theappropriate height and angle, the handle 82 is released to cause thesplit nut 72 to engage the screw 71 and the gear 67 to engage the rack68.

With the probe positioned, the variable transformer 117 is adjusted toprovide a selected scan motor speed. The potentiometer 155 is shifted toa desired position to provide appropriate indexing time delay andtherefore appropriate spacing between the longitudinal paths of travel.

Once all the adjustments are made, the scan control switch 101 may beclosed and the scan will commence. Further adjustments may be made asthe scan is progressing, if desired, but normally constant speed andspacing throughout the study is preferred. As the study progresses, theboom will shift longitudinally forward until one of the reversingswitches is actuated. Thereafter the boom will shift from right towardsthe left the predetermined indexing amount and then travel to therearward extremity of the longitudinal travel. When the boom reaches itsrearward extremity, the right-to-left indexing is repeated and the boomagain will move forward.

It will thus be seen that a novel and improved device has been describedin which a scan study somewhat in the shape of a square wave isconducted. The probe is shifted rectilinearly forward, over, back, over,forward, etc. to describe this pattern which suggests a square wave.

Although the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of example,and that numerous changes in the details of the description and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. A scanning device comprising, a frame, a driven member reciprocallycarried by the frame, the driven member being reciprocal relative to theframe in both longitudinal and transverse directions, first drive meansoperably connected to the frame and to the driven memher to shift thedriven member relative to the frame reciprocally along a longitudinalpath, second drive means to shift the driven member relative to theframe along a transverse path when the first drive means is notoperating, said driven member having an end portion projecting from theframe cantilever fashion with the end of said portion being spaced fromthe frame at all times, impulse emitting means carried by the drivenmember near said one end, said impulse means being spaced from saidframe and responsive to radiation, and visual image record producingmeans operably connected to the driven member to record a graphic imagein response to impulses from said impulse emitting means.

2. The device of claim 1 wherein the driven member is a boom transverseof the frame and projects from both sides thereof.

3. A scintillation scanning device comprising, a frame 10 and housingstructure, the housing defining a scan control space therein, thehousing having first and second oppositely located access aperturescommunicating with said space, a scan boom movably supported by saidframe and extending through said space and said apertures, rcciprocaldrive means carried in said housing and disposed at least in part withinsaid space, said reciprocal drive means being operably connected to saidboom to drive the boom reciprocally in a longitudinal scanning path,transverse drive means carried in said housing and disposed at least inpart within said space, said transverse drive means being operablyconnected to said boom to move said boom transversely in a scan indexingpath, a scintillatioin responsive element supported at one end of saidboom, a graph producing stylus supported at the other end of the boom,:1 light source carried in the housing and operably connected to saidboom to move therewith, and impulse transmission means connecting saidelement to said stylus and to said light source to transmit impulsesfrom the element to the light source and stylus.

4. A scintillation scanning device comprising, a frame and housingstructure, a housing defining a scan control space therein, the housinghaving first and second oppositely located access aperturescommunicating with said space, a scan boom movably supported by saidframe and extending through said space and said apertures, reciprocaldrive means carried in said housing and disposed at least in part withinsaid space, said reciprocal drive means being operably connected to saidboom to drive the boom reciprocally in a longitudinal scanning path,transverse drive means carried in said housing and disposed at least inpart within said space, said transverse drive means being operablyconnected to said boom to move said boom transversely in a scan indexingpath, a scintillation responsive element supported on said boom on oneside of the housing, said housing defining a light tight region, meansto selectively position a photographic film in said light tight region,a light source carried in the light tight region and operably connectedto said boom to move therewith, and impulse transmission meansconnecting said element to said stylus and to said light source totransmit impulses from the element to the light source and stylus.

5. A scintillation scanning device comprising, a frame and housingstructure, the housing defining a scan control space therein, thehousing having first and second oppositely located access aperturescommunicating with said space, a scan boom movably supported by saidframe and extending through said space and said apertures, reciprocaldrive means carried in said housing and disposed at least in part withinsaid space, said reciprocal drive means being operably connected to saidboom to drive the boom reciprocally in a longitudinal scanning path,transverse drive means carried in said housing and disposed at least inpart within said space, said transverse drive means being operablyconnected to said boom to move said boom transversely in a scan indexingpath, control means connected to said reciprocal drive means and to saidtransverse drive means to selectively connect and disconnect saidoperable connections, said boom being movable manually when saidoperable connections are disconnected, a scintillation responsiveelement supported on said boom at one side of the housing, and imageproducing means for connection to the scintillation element forproviding a graphic representation of an object being studied inresponse to impulses emitted by said element.

6. A scintillation scanner comprising, a housing, a driven memberassembly, carriage means supporting the driven member assembly andcarried by the housing, said carriage means including means to permitthe driven member assembly to move longitudinally and transverselyrelative to the housing said housing defining a light tight filmreceiving chamber, the housing also defining a film chamher access slot,[at light source support carried by the driven member for movementtherewith, the support] one portion of the assembly being disposedthrough said slot and into the chamber, a light source forming a part ofsaid assembly and mounted on [the support and] said one assemblyportion, said light source being disposed in the chamber, said assemblyhaving an end portion projecting from the housing cantilever fashionwith the end of said end portion being spaced from the frame and saidone portion at all times, a scintillation responsive element forming apart of said assembly and carried {by the driven member for connection]near said end and spaced from the housing, the responsive element beingelectrically connected to the light source, and light tight meansclosing said access slot to permit movement of the [support] oneassembly portion transversely of the slot While maintaining said filmchamber light tight.

7. A scintillation scanner comprising, a housing, a driven memberassembly, carriage means supporting the driven member assembly andcarried by the housing, said carriage including means to permit thedriven member assenibly to move longitudinally and transversely relativeto the housing, said housing defining a light tight film receivingchamber, the housing also defining a film chamber access slot, [a phototube support carried by the driven member for movement therewith, thesupport] one portion of the assembly being disposed through said slotand into the chamber, said assembly including a photo tube mounted on[the support] said one portion and disposed in the chamber, saidassembly having an end portion projecting from the housing cantileverfashion with the end of said end portion being spaced from the frame andsaid one portion at all times, said assembly also including ascintillation responsive element carried [by the driven member forconnection] near said end and spaced from the housing, the responsiveelement being electrically connected to the tube, a constant tensioncoil spring closing said slot, :1 pair of rotatable spaced spoolssupporting the ends of said spring, said spring having an openingtherethrough, said [support] one portion being disposed through saidopening, and means interposed between the spring and the [support] oneportion to permit longitudinal movement of the support transversely ofthe spring.

8. A drive assembly for moving a body serially along parallel pathscomprising, a support, a carriage movably mounted on the support, a bodymovably mounted on the carriage, a rack connected to the body, a bracketcarried by the carriage, a gear carried by the bracket and selectivelyengageable with the rack, a drive screw carried by the support anddisposed transversely of the rack, a split r nut carried by the carriageand selectively engageable with the screw, a rotatable shaft mounted onthe carriage and having first and second spaced cams thereon, the firstcam being coactable with the split nut and the second cam beingconstable with the bracket, the shaft and cams having a disengagementposition and an engagement position, the split nut and gear being inengagement with the screw and rack respectively when the cams are in theengagement position, the nut and the gear being disengaged from thescrew and rack respectively when the cams are in the disengagementposition, a reversible electric motor connected to the gear tosequentially drive the gear in opposite directions, limit switch meansselectively positionable on the carriage for activation by a selectedextreme of body travel and to reverse the reversible motor whenactivated, a drive motor operatively connected to the screw for rotationthereof, and means to energize said drive motor when said limit switchesare activated to index the body transversely.

9. A scanning device comprising, a frame member defining a transverseguide track, a carriage member reciprocally carried on the frame memberguide track, the carriage member defining a guide track disposedtransversely of the frame member guide track, a boom elementreciprocally mounted on the carriage guide track, a rotatable wormmounted on one of the members, a split nut mounted on the other of themembers and engageable with the screw, means to selectively open the nutto disengage it from the screw and to selectively close the out intoengagement with the screw, said carriage and boom being relativelyreciprocal elements, a rack carried by one of the elements, a gearcarried by the other of the elements, means to shift the gear relativeto the rack selectivcly into and out of engagement with the rack,reversible means to cause rotation of the gear relative to the rack, andmeans to cause relative rotation of the nut and screw.

10. [In a device having a body for transcribing] a seintillation scannercomprising:

(a) housing and frame structure including an access opening;

(b) a boom extending through the opening and having one portionsupported within the structure and an end portion projecting cantileverfashion therefrom, said boom being adapted to transcribe a wave likepath,

(c) a [body] boom drive mechanism in the structure and connected to theboom, saitl mechanism comprising:

(i) a first drive means for driving the [body] boom along a reciprocalpath (ii) a second drive means for shifting the [body] boom along atransverse path (iii) settable means to define the limits of thelongitudinal path (iv) means actuated by the settable means to reversethe direction of the first means (v) means actuated by the settablemeans to actuate the second drive means [,1 and,

(vi) time delay means actuated by the settable means to maintain thefirst drive means inoperative while the second drive means is inoperation.

11. The device of claim 10 wherein the time delay means includes acapacitor.

12. The device of claim 10 wherein the time delay means is adjustableand wherein the time delay means causes the closing of a circuit toactuate the first drive means and simultaneous opening of a circuit tostop the second drive means after an adjusted time interval.

13. In a scintillation scanning device a recording apparatus forproducing a graphic image comprising, a stylus housing having a throughpassage, a support for a graph providing sheet having a generally flatgraph producing surface transverse of the housing passage and spacedtherefrom, a stylus carried in the housing passage and movablelongitudinally therein from a surface abutment position to a storageposition, a stylus positioning member having a pivot end and a stylusabutment end, the housing including a positioning member pivot endsupport element pivotally connected to the pivot end, said element beingmovable transversely of the passage and relative to the housing, meansurging the element toward the passage to maintain the member abutmentend in abutment with the stylus, the member being pivotally movable overcenter and against the action of the urging means from a first to asecond position, said stylus being in the surface abutment position whenthe member is in the first position and in the storage position when themember is in the second position, and said member stylus abutment endbeing operatively connected to the stylus such that movement of themember from one extreme position to the other causes movement of thestylus.

14. [In a mechanism of the class described] A scintillation scannercomprising:

(a) housing and frame structure including an access opening; (b) a boomextending through the opening and having one portion supported withinthe structure and an end portion projecting cantilever fashiontl'terefrotu;

(c) a boom drive mechanism carried by the structure and connected to theboom comprising [,1];

(i) a reversible drive motor for shifting [a body] the boom in areciprocal path, a drive electric circuit connected to the drive motorand to a source of electrical potential, said drive circuit includingmeans to reverse the direction of motor operation L];

(ii) first and second settable means positionable in seelcted positionsat the extremes of such reciprocal path, said settable means includingmeans to actuate said reversing means L];

(iii) an indexing motor L];

(iv) an indexing circuit connecting the indexing motor to a source ofelectric potential, said indcxing circuit including a normally openswitch and means to close said switch (v) said settable means includingmeans to actuate said switch closing means and,

(vi) said drive circuit including time delay means to delay thereversing of said drive motor when said settable means actuates saidreversing means.

, 15. An electric circuit for driving an object over a scanning pathcomprising, a transformer connected to a source of electric potential,first and second rectifiers, a voltage control means series connected tothe first rectifier and to the transformer, the second rectifier beingconnected to the transformer in parallel with the first rectifier andthe voltage control means, a DC. motor having an armature connected tosaid first rectifier, a reversing switch series connected with saidfirst rectifier and said armature, said DC. motor having a fieldconnected to said second rectifier, a normally closed DC. motor controlswitch series connected to one of the rectifiers, a motor control switchactivation solenoid connected to the other of said rectifiers, acapacitor connected in series with said solenoid, a solenoid controlswitch connected in series with said motor control solenoid and parallelcapacitor, first and second normally open parallel connected time delayswitches, said time delay parallel circuit being in series with saidsolenoid, a reversing control solenoid, a normally open reversing limitswitch and a normally closed reversing limit switch connected in serieswith one another and the solenoid, a direction maintenance actuated bythe reversing control solenoid and connected in parallel with thenormally open reversing limit switch, the direction maintenance switchbeing operably connected mechanically to the re versing switch andseries connected to the normally closed reversing limit switch and thereversing solenoid, first and second parallel connected time delayswitches operably connected mechanically to the open and closedreversing limit switches respectively, said time delay switches beingconnected in parallel with one another and in series with the motorcontrol solenoid, an alternating current motor connected to a source ofelectric potential, and a normally open AC. motor actuation switchseries connected to said AC. motor and operably connected mechanicallyto said motor control switch, and to said solenoid control switch, andsaid motor control solenoid being positioned to actuate said motorcontrol switch, said solenoid control switch, and said AC. motoractuation switch.

16. A scintillation scanner comprising, a housing and frame structure,floor wheels connected to and supporting the structure for movement overa floor, the structure including horizontally disposed tracks near thetop thereof, a carriage reciprocally mounted on the tracks, firstreciprocal drive means connected to the carriage to cause selectivereciprocal movement along the tracks, a driven member reciprocallymounted on the carriage and including an end portion projectingcantilever fashion from the structure, the end of said portion beingspaced from the structure at all times, second reciprocal drive meansconnected to the driven member for causing selective rccipro cation ofthe driven member, control means connected to each of the drive meansfor selectively energizing the drive means one at a time, limit switchesadjustably mounted on said structure each positionable for actuation byone of the reciprocal members to delineate a limit of at least onereciprocal movement [and] each limit switch being elec tricallyconnected to the control means to actuate the control means to alter therecpirocal movement when one limit of reciprocable movement is reached,a scintillation responsive member carried by said driven member nearsaid one end and adapted to emit impulses in response to detectedradiation, and visual image producing means connected to the drivenmember at a location spaced from said one portion and electricallyconnected to said responsive member to produce a visual imagecorresponding to the detected radiation.

17. A scintillation scanner comprising a housing and frame structure,floor wheels connected to and supporting the structure for movement overa fioor, the structure including horizontally disposed tracks near thetop thereof, a carriage reciprocally mounted on the tracks, firstreciprocal drive means connected to the carriage to cause selectivereciprocal movement along the tracks, a driven member reciprocallymounted on the carriage and including on end portion projectingcantilever fashion from the structure, the end of said portion beingspaced from the structure at all times, second reciprocal drive meansconnected to the driven member for causing selective reciprocation ofthe driven member, control means connected to each of the drive meansfor selectively energizing the drive means one at a time. said controlmeans including means to adjust the speed of each of said drive means,[and] settable means carried by said structure and positioned to actuatesaid control means when one of a plurality of predetermined limits ofreciprocal travel is reached, a scintillation responsive member carriedby said driven member near said one end and adapted to emit impulses inresponse to detected radiation, and visual image producing meansconnected to the driven member at a location spaced from said oneportion and electrically connected to said responsive member to producea visual image corresponding to the detected radiation,

18. A scintillation scanner comprising a housing and frame structureincluding an access opening. the structure including horizontal tracks,a carriage member reciprocally mounted on the tracks, first reciprocaldrive means connected to the carriage to cause selective reciprocal movement along the tracks, a driven boom member reciprocally mounted on thecarriage member and projecting through the opening, said boom memberincluding an end portion projecting cantilever fashion past said housingand frame structure, second reciprocal drive means connected to thedriven member for causing selective reciprocation of the driven member,manually actuatable means connected to at least one of the drive meansto disable the one drive means and permit manual adjustment of themember driven by the one drive means, said manual means normallyenabling the one drive means, [and] control means connected to each ofthe drive means for energizing the drive means, a scintillationresponsive member carried by said driven member near said one end andadapted to emit impulses in response to detected radiation, and visualimage producing means connected to the driven member at a locationspaced from said one portion and electrically connected to saidresponsive member to produce a visual image corresponding to thedetected radiation.

19. The device of claim 18 wherein the manually actuatable meansincludes a shaft, a handle on the shaft external of said structure, anda cam on the shaft to disable said one drive means when the shaft isrotated to a disabling position.

20. The device of claim 18 wherein the manually actuatable means isoperably connected to both of said drive means to simultaneously disablethe same when the manually actuatable means is actuated.

21. In combination a frame including a track, a carriage reciprocallycarried on the track, a driven member reciprocally carried on thecarriage, first drive means between the frame and the carriage fordriving the carriage along the track, second drive means between thecarriage and the driven member for causing reciprocal movement of thedriven member relative to the carriage, a manually rotatable shaftcarried by the carriage, and first and second cam means carried on theshaft and operatively connected to the first and second drive meansrespectively for selectively and simultaneously disabling both suchdrive means to permit manual movement of the driven member.

22. The device of claim 21 wherein one of the drive means includes asplit nut engaging a worm and the other includes a rack and gear andwherein the split nut is opened and the rack is disengaged from the gearwhen the two drive means are disabled.

23. A scintillation scanner comprising a housing and frame structure,floor wheels connected to and supporting the structure for movement overa floor, the structure including horizontally disposed tracks near thetop thereof, a carriage reciprocally mounted on the tracks, firstreciprocal drive means connected to the carriage to cause selectivereciprocal movement along the tracks, a driven member reciprocallymounted on the carriage, and including an end portion projectingcantilever fashion from the structure, the end of said portion beingspaced from the structure at all times, second reciprocal drive meansconnected to the driven member for causing selective reciprocation ofthe driven member, control means connected to each of the drive meansfor selectively energizing the drive means one at a time, said controlmeans including means to adjust the speed of each of said drive means,settable means carried by said structure and positioned to actuate saidcontrol means when one of a plurality of predetermined limits ofreciprocal travel is reached, [and] said control means including timedelay disabling and reversing means to disable one of said drive meansfor a predetermined time interval and to enable said one drive means ina reverse direction after said interval and to energize the other ofsaid drive means during said time interval only, a scintillationresponsive member carried by said driven member near said one end andadapted to emit impulses in response to detected radiation, and visualimage producing means connected to the driven member at a locationspaced from said one portion and electrically connected to saidresponsive member to produce a visual image corresponding to thedetected radiation.

24. A scintillation scanner comprising, a housing and frame structure, asupport member movably mounted on the housing frame structure, meansinterposed between the member and the structure to drive the member overa scan path, impulse emitting means connected to the support member andresponsive to emitting radiation, said structure including a sheetsupport for a graph providing sheet, the sheet support having agenerally flat sheet supporting surface, a stylus housing connected tosaid support member, the stylus housing including a through passage, astylus carried in the housing passage and movable longitudinally thereintoward and away from said surface, from a sheet abutment position to astorage position, said stylus being electrically connected to saidimpulse emitting means for transmitting impulses received from saidimpulse emitting means to a graph providing sheet, said stylus andimpulse emitting means being movable together with said support memberover said scan path while maintaining the stylus above said sheet, astylus positioning member having a pivot end and a stylus abutment end,the stylus housing including a positioning member pivot and supportelement pivotally connected to the pivot end, said element being movabletransversely of the said passage and relative to the stylus housing,means urging the element toward the passage to maintain the positioningmember abutment end in abutment with the stylus, a positioning memberbeing pivotally movable over center and against the action of the urgingmeans from a first to a second position, the stylus being in the sheetabutment position when the positioning member is in the first positionand in the storage position when the positioning member is in the secondposition, and said positioning member stylus abutment end beingoperatively connectable to the stylus such that movement of the memberfrom one extreme position to the other causes movement of the stylus.

25. A scintillation scanner comprising a housing and frame structure,said structure including horizontal tracks, a carriage memberreciprocally mounted on the tracks, a first means connected to thecarriage member and said structure to cause selective reciprocablemovement of the carriage along the track, a driven member reciprocallymounted on the carriage member, a second means interposed between themembers to cause selective reciprocation of the driven member relativeto the carriage member, control means connected to each of the numberedmeans for selectively energizing the numbered means one at a time, oneof said numbered means being a drive means and the other of saidnumbered means being an indexing means, said drive means including areversible drive motor for shifting one of the members in a reciprocalpath, said control means including a drive electric circuit electricallyconnected to the drive motor and to a source of electric potential, saiddrive circuit including means to reverse the direction of motoroperation, said control means also including first and second settablemeans carried by said structure and positionable in selected positionsat the extremes of such reciprocal path, said settable means includingmeans to actuate said reversing means, said indexing means including anindexing motor, said control means also including an indexing circuitconnecting said indexing motor to a source of electric potential, saidindexing circuit including a normally open switch and means to closesaid switch, said settable means including means to actuate said switchclosing means and drive circuit including a time delay means to delaythe reversing of said drive motor when said settablc means actuates saidreversing means.

26. A scintillation scanner comprising, a housing and frame structurehaving upright side walls, said upright side walls including a spacedpair of transversely extending apertures, longitudinal tracks withinsaid structure, a carriage within said structure and reciprocallymounted on said tracks, a boom reciprocally carried on said carriage andextending through both of said apertures, a first drive means interposedbetween the carriage and the frame structure for driving said carriageacross said frame, a second drive means interposed between the carriageand the boom for driving the boom reciprocally relative to the carriage,an impulse emitting scintillation responsive member connected to theboom near one end thereof and exteriorly of said structure, a graphproducing means connected to the boom near the other end thereof andalso exteriorly of said structure, and control means within saidstructure connected to said drive means for selectively actuating saiddrive means.

27. A scanning device comprising, a frame a boom reciprocally carried bythe frame, the boom being reciprocal relative to the frame in bothlongitudinal and transverse directions, drive means operably connectedto the frame and to the boom to shift the boom relative to the framereciprocally along a longitudinal path and to shift the boom relative tothe frame along a transverse path, impulse emitting means carried by theboom and responsive to radiation, visual image record producing meansoperably connected to the boom to record a graphic image in response toimpulses from said impulse emitting means, and said visual imagerecording and producing means including a stylus for conductingelectrical impulses to an impulse responsive sheet, said styluscomprising a wood insulator having a wood bore and a nonmetallicelectric conductor filling the bore, said conductor consistingessentially of a quantity of powdered graphite and a binder.

28. The device of claim 1 wherein the scanning device includes a stylushousing having a through passage, a support for a graph providing sheethaving a generally flat graph producing surface transverse of thehousing aperture and spaced therefrom, a stylus carried in the housingaperture and movable longitudinally therein from a surface abutmentposition to a storage position, a stylus positioning member having apivot end and a stylus abutment and, the housing including a positioningmember pivot and support element pivotally connected to the pivot end,said element being movable transversely of the aperture and relative tothe housing, means urging the element toward the aperture to maintainthe member abutment end in abutment with the stylus, the member beingpivotally movable over center and against the action of the urging meansfrom a first to a second position, said stylus being in the surfaceabutment position when the member is in the first position and in thestorage position when the member is in the second position, and saidmember stylus abutment end being operatively connected to the stylussuch that movement of the member from one extreme position to the othercauses movement of the stylus.

29. In the device of claim 1 the first and second drive means including,a reversible drive motor for shifting a boom in a reciprocal path, adrive electric circuit connected to the drive motor and to a source ofelectric potential, said drive circuit including means to reverse thedirection of motor operation, first and second settable meanspositionable in selected positions at the extremes of such reciprocalpath, said settable means including means to actuate said reversingmeans, an indexing motor, and in indexing circuit connecting the motorto a source of electric potential, said circuit including a normallyopen switch and means to close said switch, said settable meansincluding means to actuate said switch closing means, and said drivecircuit including time delay means to delay the reversing of said drivemotor when said settable means actuate said reversing means.

References Cited by the Examiner The following references, cited by theExaminer, are of record in the patented file of this patent or theoriginal patent.

18 UNITED STATES PATENTS 1,865,610 7/1932 Blair 10l26 2,164,946 7/1939Scheppmann 346-141 2,351,319 6/1944 Chase 346-141 2,370,163 2/1945 Hare25083.6 2,454,711 11/1948 Odell 346-104 2,554,323 5/1951 Cade 3461042,639,625 5/1953 Geyer 74-424.8 2,677,797 5/1954 Sher 318282 2,703,4983/1955 Tree 74424.8 2,776,377 1/1957 Anger 250-71.5 2,859,396 11/1958King 318-282 2,889,463 6/1959 Linsert et a1. 250-833 2,922,887 1/1960Jacobs 25083.3 2,967,939 1/1961 Caha et a1. 250-83.3

FOREIGN PATENTS 1,023,826 2/1958 Germany. 1,026,008 3/1958 Germany.

OTHER REFERENCES Bender et al.: A Versatile High-Contrast Photoscannerfor the Localization of Human Tumors With Radioisotopes, InternationalJournal of Applied Radiation and Isotopes, 1959, vol. 4, pages 154-161,Pergamon Press Ltd.

British Journal of Applied Physics, vol. 4, page 353, 1953.

Green et al.: A Free-Moving Isidose Tracing Machine, Nucleonics, April1958, pp. 92-94.

A High Contrast Photographic Recorder for Scintillation CounterScanning, from Radiology, May 1956, pages 730 to 739.

MacIntyre et al.: Techniques for the Visualization of Internal Organs byan Automatic Radioisotope Scanning System, International Journal ofApplied Radiation and Isotopes, 1958, vol. 3, pages 193-206, PergamonPress Ltd.

Mauchel et al.: Automatic Isidose Plotter, Nuclconics, December 1954,pp. and 51.

Reid et al.: An Automatic Brain Scanner, International Journal ofApplied Radiation and Isotopes, 1958, vol. 3, pages 1-7, Pergamon Press,Ltd, London.

Sopp et al.: Economical Scintillation Scanner, Nucleonics, v. 12, #12,December 1954, page 49.

RALPH G. NILSON, Primary Examiner.

A. R. BORCHELT, Assistant Examiner.

